In the universal system of notation, the deciduous mandibular second molars are designated by a letter written in uppercase.

In the universal system of notation, the permanent mandibular second molars are designated by a number.

In the Palmer notation, a number is used in conjunction with a symbol designating in which quadrant the tooth is found.

The international notation has a different numbering system from the previous two, and the right permanent mandibular second molar is known as "47", and the left one is known as "37".

An eighth cusp was found in a primary second lower molar in an Argentinean child.